Buying Diamond Jewellery

Your guide to buying diamond engagement rings and jewellery.

Metal Type

Firstly you have to consider the metal type. Gold, or platinum? Gold tends to make people think of the traditional yellow kind but there are in fact many different types including rose gold and white gold which looks silver.

White gold was originally developed as a substitute for platinum and is alloyed with at least one white metal. Its colour is closer to grey, so it's often coated with rhodium to give it a brighter finish. It is very popular but you will have to get it re rhodium plated every few years depending on the wear caused by the individuals lifestyle. The cost for this is $80 and takes about 2-3 days.

Platinum is one of the toughest metals and because of its strength, jewellery can be made from almost pure platinum.

Most precious metals are too soft in their pure form to make jewellery, so they’re alloyed with other metals. Jewellery made of a precious metal should be stamped to show its purity – either as carats or millesimal fineness.

Some countries overseas use "karat" for metals and "carat" for gems, but in New Zealand we don't distinguish in this way, using "carat" for both.

Carats in metal indicate the purity and are measured in units of 24. 24ct is 99+ percent pure, whereas 14ct is 14 parts metal and 10 parts alloy, or 58.5 percent pure and the number will be stamped on the item. 24ct gold is very soft so we tend to recommend 14ct gold as it is a bit more durable.

Gem quality

When it comes to gems, carats refer to weight rather than the alloy mix. 1.00ct of gem weight equals 0.2 grams (about the weight of a paperclip).

The way a gem is cut draws the eye to the richness of its colour and brilliance, the better the cut the better the diamond will preform. Clarity refers to the flaws, known as inclusions, in a gem.

Fun fact: The most expensive diamond ever sold in New Zealand was a 4.85 carat for $229,000 in 2011 in Auckland.

Buying quality locally.

Well-known chain stores sell mass produced products all throughout New Zealand but here at Polished Diamonds in Christchurch you can get unique custom made jewellery for a competitive price .

Polished Diamonds are members of the Jewellers and Watchmakers of New Zealand. This is a good thing to check for any jewellery store as all members are bound by a code of conduct and it provides a process of arbitration if there is a problem that can't be resolved.

Insurance and Valuations

Precious diamond jewellery is valuable and easy for thieves to transport – or for owners to lose! A common problem is that people assume jewellery is automatically covered by house and contents insurance. Policies often do cover such items as "unspecified jewellery" or "personal effects". But if the cover is unspecified, it will have a limit – usually between $2500 and $3000.

To get an item insured you’ll also need to prove ownership by providing original receipts or valuations. If you can't prove you owned it in the first place your claim may be declined.

The value of a jewellery item is subject to fluctuation along with current exchange rates and the price of metals and precious stones. The best way to have your item insured for its value is to provide a valuation.